Refactor C API string getters to return allocated strings

lijy91 · lijy91 · commit 62ed26fe9aed · 2025-10-08T20:44:25.000+08:00
Changed native_menu_item_get_label, native_menu_item_get_icon, native_menu_item_get_tooltip, and native_keyboard_accelerator_to_string to return newly allocated C strings instead of writing to caller-provided buffers. Updated documentation and example usage to reflect new memory management requirements. This improves usability and safety for string handling in the C API.
diff --git a/examples/tray_icon_c_example/main.c b/examples/tray_icon_c_example/main.c
@@ -11,12 +11,14 @@
 // Include individual C API headers instead of the full nativeapi.h
 #include "../../src/capi/menu_c.h"
 #include "../../src/capi/run_example_app_c.h"
+#include "../../src/capi/string_utils_c.h"
 #include "../../src/capi/tray_icon_c.h"
 #include "../../src/capi/tray_manager_c.h"
 
 // Event callback functions
 void on_menu_item_clicked(const void* event, void* user_data) {
-  const native_menu_item_clicked_event_t* clicked_event = (const native_menu_item_clicked_event_t*)event;
+  const native_menu_item_clicked_event_t* clicked_event =
+      (const native_menu_item_clicked_event_t*)event;
   printf("Menu item clicked: ID=%ld, Text='%s'\n", clicked_event->item_id,
          clicked_event->item_text);
 
@@ -29,28 +31,35 @@ void on_menu_item_clicked(const void* event, void* user_data) {
 }
 
 void on_tray_clicked(const void* event, void* user_data) {
-  const native_tray_icon_clicked_event_t* clicked_event = (const native_tray_icon_clicked_event_t*)event;
-  printf("Tray icon clicked! ID=%ld, Button='%s'\n", clicked_event->tray_icon_id,
-         clicked_event->button);
+  const native_tray_icon_clicked_event_t* clicked_event =
+      (const native_tray_icon_clicked_event_t*)event;
+  printf("Tray icon clicked! ID=%ld, Button='%s'\n",
+         clicked_event->tray_icon_id, clicked_event->button);
 }
 
 void on_tray_right_clicked(const void* event, void* user_data) {
-  const native_tray_icon_right_clicked_event_t* right_clicked_event = (const native_tray_icon_right_clicked_event_t*)event;
-  printf("Tray icon right clicked! ID=%ld\n", right_clicked_event->tray_icon_id);
+  const native_tray_icon_right_clicked_event_t* right_clicked_event =
+      (const native_tray_icon_right_clicked_event_t*)event;
+  printf("Tray icon right clicked! ID=%ld\n",
+         right_clicked_event->tray_icon_id);
 }
 
 void on_tray_double_clicked(const void* event, void* user_data) {
-  const native_tray_icon_double_clicked_event_t* double_clicked_event = (const native_tray_icon_double_clicked_event_t*)event;
-  printf("Tray icon double clicked! ID=%ld\n", double_clicked_event->tray_icon_id);
+  const native_tray_icon_double_clicked_event_t* double_clicked_event =
+      (const native_tray_icon_double_clicked_event_t*)event;
+  printf("Tray icon double clicked! ID=%ld\n",
+         double_clicked_event->tray_icon_id);
 }
 
 void on_menu_opened(const void* event, void* user_data) {
-  const native_menu_opened_event_t* open_event = (const native_menu_opened_event_t*)event;
+  const native_menu_opened_event_t* open_event =
+      (const native_menu_opened_event_t*)event;
   printf("Menu opened: ID=%ld\n", open_event->menu_id);
 }
 
 void on_menu_closed(const void* event, void* user_data) {
-  const native_menu_closed_event_t* close_event = (const native_menu_closed_event_t*)event;
+  const native_menu_closed_event_t* close_event =
+      (const native_menu_closed_event_t*)event;
   printf("Menu closed: ID=%ld\n", close_event->menu_id);
 }
 
@@ -104,10 +113,14 @@ int main() {
   native_menu_item_set_state(checkbox, NATIVE_MENU_ITEM_STATE_CHECKED);
 
   // Set up event listeners using new API
-  native_menu_item_add_listener(item1, NATIVE_MENU_ITEM_EVENT_CLICKED, on_menu_item_clicked, NULL);
-  native_menu_item_add_listener(item2, NATIVE_MENU_ITEM_EVENT_CLICKED, on_menu_item_clicked, NULL);
-  native_menu_item_add_listener(exit_item, NATIVE_MENU_ITEM_EVENT_CLICKED, on_menu_item_clicked, NULL);
-  native_menu_item_add_listener(checkbox, NATIVE_MENU_ITEM_EVENT_CLICKED, on_menu_item_clicked, NULL);
+  native_menu_item_add_listener(item1, NATIVE_MENU_ITEM_EVENT_CLICKED,
+                                on_menu_item_clicked, NULL);
+  native_menu_item_add_listener(item2, NATIVE_MENU_ITEM_EVENT_CLICKED,
+                                on_menu_item_clicked, NULL);
+  native_menu_item_add_listener(exit_item, NATIVE_MENU_ITEM_EVENT_CLICKED,
+                                on_menu_item_clicked, NULL);
+  native_menu_item_add_listener(checkbox, NATIVE_MENU_ITEM_EVENT_CLICKED,
+                                on_menu_item_clicked, NULL);
 
   // Add items to menu
   native_menu_add_item(menu, item1);
@@ -119,8 +132,10 @@ int main() {
   printf("Added %zu items to menu\n", native_menu_get_item_count(menu));
 
   // Set menu event listeners using new API
-  native_menu_add_listener(menu, NATIVE_MENU_EVENT_OPENED, on_menu_opened, NULL);
-  native_menu_add_listener(menu, NATIVE_MENU_EVENT_CLOSED, on_menu_closed, NULL);
+  native_menu_add_listener(menu, NATIVE_MENU_EVENT_OPENED, on_menu_opened,
+                           NULL);
+  native_menu_add_listener(menu, NATIVE_MENU_EVENT_CLOSED, on_menu_closed,
+                           NULL);
 
   // Create a submenu example
   native_menu_t submenu = native_menu_create();
@@ -164,9 +179,13 @@ int main() {
   native_tray_icon_set_context_menu(tray_icon, menu);
 
   // Set up tray icon event listeners using new API
-  native_tray_icon_add_listener(tray_icon, NATIVE_TRAY_ICON_EVENT_CLICKED, on_tray_clicked, NULL);
-  native_tray_icon_add_listener(tray_icon, NATIVE_TRAY_ICON_EVENT_RIGHT_CLICKED, on_tray_right_clicked, NULL);
-  native_tray_icon_add_listener(tray_icon, NATIVE_TRAY_ICON_EVENT_DOUBLE_CLICKED, on_tray_double_clicked, NULL);
+  native_tray_icon_add_listener(tray_icon, NATIVE_TRAY_ICON_EVENT_CLICKED,
+                                on_tray_clicked, NULL);
+  native_tray_icon_add_listener(tray_icon, NATIVE_TRAY_ICON_EVENT_RIGHT_CLICKED,
+                                on_tray_right_clicked, NULL);
+  native_tray_icon_add_listener(tray_icon,
+                                NATIVE_TRAY_ICON_EVENT_DOUBLE_CLICKED,
+                                on_tray_double_clicked, NULL);
 
   // Show the tray icon
   if (native_tray_icon_show(tray_icon)) {
@@ -191,10 +210,10 @@ int main() {
     // Get accelerator info
     native_keyboard_accelerator_t accel;
     if (native_menu_item_get_accelerator(found_item, &accel)) {
-      char accel_str[64];
-      if (native_keyboard_accelerator_to_string(&accel, accel_str,
-                                                sizeof(accel_str)) > 0) {
+      char* accel_str = native_keyboard_accelerator_to_string(&accel);
+      if (accel_str) {
         printf("Exit item accelerator: %s\n", accel_str);
+        free_c_str(accel_str);  // Free the allocated string
       }
     }
   }
diff --git a/src/capi/menu_c.cpp b/src/capi/menu_c.cpp
@@ -231,25 +231,22 @@ void native_menu_item_set_label(native_menu_item_t item, const char* label) {
   }
 }
 
-int native_menu_item_get_label(native_menu_item_t item,
-                               char* buffer,
-                               size_t buffer_size) {
-  if (!item || !buffer || buffer_size == 0)
-    return -1;
+char* native_menu_item_get_label(native_menu_item_t item) {
+  if (!item)
+    return nullptr;
 
   try {
     auto menu_item = static_cast<MenuItem*>(item);
     std::string text = menu_item->GetLabel();
-
-    if (text.length() >= buffer_size) {
-      return -1;
+    
+    // Allocate C string and copy content
+    char* result = static_cast<char*>(malloc(text.length() + 1));
+    if (result) {
+      strcpy(result, text.c_str());
     }
-
-    strncpy(buffer, text.c_str(), buffer_size - 1);
-    buffer[buffer_size - 1] = '\0';
-    return static_cast<int>(text.length());
+    return result;
   } catch (...) {
-    return -1;
+    return nullptr;
   }
 }
 
@@ -265,25 +262,22 @@ void native_menu_item_set_icon(native_menu_item_t item, const char* icon) {
   }
 }
 
-int native_menu_item_get_icon(native_menu_item_t item,
-                              char* buffer,
-                              size_t buffer_size) {
-  if (!item || !buffer || buffer_size == 0)
-    return -1;
+char* native_menu_item_get_icon(native_menu_item_t item) {
+  if (!item)
+    return nullptr;
 
   try {
     auto menu_item = static_cast<MenuItem*>(item);
     std::string icon = menu_item->GetIcon();
-
-    if (icon.length() >= buffer_size) {
-      return -1;
+    
+    // Allocate C string and copy content
+    char* result = static_cast<char*>(malloc(icon.length() + 1));
+    if (result) {
+      strcpy(result, icon.c_str());
     }
-
-    strncpy(buffer, icon.c_str(), buffer_size - 1);
-    buffer[buffer_size - 1] = '\0';
-    return static_cast<int>(icon.length());
+    return result;
   } catch (...) {
-    return -1;
+    return nullptr;
   }
 }
 
@@ -300,25 +294,22 @@ void native_menu_item_set_tooltip(native_menu_item_t item,
   }
 }
 
-int native_menu_item_get_tooltip(native_menu_item_t item,
-                                 char* buffer,
-                                 size_t buffer_size) {
-  if (!item || !buffer || buffer_size == 0)
-    return -1;
+char* native_menu_item_get_tooltip(native_menu_item_t item) {
+  if (!item)
+    return nullptr;
 
   try {
     auto menu_item = static_cast<MenuItem*>(item);
     std::string tooltip = menu_item->GetTooltip();
-
-    if (tooltip.length() >= buffer_size) {
-      return -1;
+    
+    // Allocate C string and copy content
+    char* result = static_cast<char*>(malloc(tooltip.length() + 1));
+    if (result) {
+      strcpy(result, tooltip.c_str());
     }
-
-    strncpy(buffer, tooltip.c_str(), buffer_size - 1);
-    buffer[buffer_size - 1] = '\0';
-    return static_cast<int>(tooltip.length());
+    return result;
   } catch (...) {
-    return -1;
+    return nullptr;
   }
 }
 
@@ -1140,26 +1131,23 @@ void native_menu_cleanup_all(void) {
   cleanup_at_exit();
 }
 
-int native_keyboard_accelerator_to_string(
-    const native_keyboard_accelerator_t* accelerator,
-    char* buffer,
-    size_t buffer_size) {
-  if (!accelerator || !buffer || buffer_size == 0)
-    return -1;
+char* native_keyboard_accelerator_to_string(
+    const native_keyboard_accelerator_t* accelerator) {
+  if (!accelerator)
+    return nullptr;
 
   try {
     KeyboardAccelerator cpp_accelerator =
         convert_keyboard_accelerator(accelerator);
     std::string str = cpp_accelerator.ToString();
 
-    if (str.length() >= buffer_size) {
-      return -1;
+    // Allocate C string and copy content
+    char* result = static_cast<char*>(malloc(str.length() + 1));
+    if (result) {
+      strcpy(result, str.c_str());
     }
-
-    strncpy(buffer, str.c_str(), buffer_size - 1);
-    buffer[buffer_size - 1] = '\0';
-    return static_cast<int>(str.length());
+    return result;
   } catch (...) {
-    return -1;
+    return nullptr;
   }
 }
diff --git a/src/capi/menu_c.h b/src/capi/menu_c.h
@@ -190,12 +190,10 @@ void native_menu_item_set_label(native_menu_item_t item, const char* label);
 /**
  * Get the label of a menu item
  * @param item The menu item
- * @param buffer Buffer to store the label (caller allocated)
- * @param buffer_size Size of the buffer
- * @return Length of the label, or -1 if buffer too small
+ * @return The label string (caller must free), or NULL if item is invalid
  */
 FFI_PLUGIN_EXPORT
-int native_menu_item_get_label(native_menu_item_t item, char* buffer, size_t buffer_size);
+char* native_menu_item_get_label(native_menu_item_t item);
 
 /**
  * Set the icon of a menu item
@@ -208,12 +206,10 @@ void native_menu_item_set_icon(native_menu_item_t item, const char* icon);
 /**
  * Get the icon of a menu item
  * @param item The menu item
- * @param buffer Buffer to store the icon path/data (caller allocated)
- * @param buffer_size Size of the buffer
- * @return Length of the icon string, or -1 if buffer too small
+ * @return The icon path/data string (caller must free), or NULL if item is invalid or no icon set
  */
 FFI_PLUGIN_EXPORT
-int native_menu_item_get_icon(native_menu_item_t item, char* buffer, size_t buffer_size);
+char* native_menu_item_get_icon(native_menu_item_t item);
 
 /**
  * Set the tooltip of a menu item
@@ -226,12 +222,10 @@ void native_menu_item_set_tooltip(native_menu_item_t item, const char* tooltip);
 /**
  * Get the tooltip of a menu item
  * @param item The menu item
- * @param buffer Buffer to store the tooltip (caller allocated)
- * @param buffer_size Size of the buffer
- * @return Length of the tooltip, or -1 if buffer too small
+ * @return The tooltip string (caller must free), or NULL if item is invalid or no tooltip set
  */
 FFI_PLUGIN_EXPORT
-int native_menu_item_get_tooltip(native_menu_item_t item, char* buffer, size_t buffer_size);
+char* native_menu_item_get_tooltip(native_menu_item_t item);
 
 /**
  * Set the keyboard accelerator for a menu item
@@ -613,12 +607,10 @@ void native_menu_item_list_free(native_menu_item_list_t list);
 /**
  * Convert keyboard accelerator to string representation
  * @param accelerator The accelerator
- * @param buffer Buffer to store the string (caller allocated)
- * @param buffer_size Size of the buffer
- * @return Length of the string, or -1 if buffer too small
+ * @return The string representation (caller must free), or NULL if accelerator is invalid
  */
 FFI_PLUGIN_EXPORT
-int native_keyboard_accelerator_to_string(const native_keyboard_accelerator_t* accelerator, char* buffer, size_t buffer_size);
+char* native_keyboard_accelerator_to_string(const native_keyboard_accelerator_t* accelerator);
 
 #ifdef __cplusplus
 }
